src/network/gethostbyname2_r.c

   1 #define _GNU_SOURCE
   2
   3 #include <sys/socket.h>
   4 #include <netdb.h>
   5 #include <string.h>
   6 #include <netinet/in.h>
   7 #include <errno.h>
   8 #include <stdint.h>
   9 #include "lookup.h"
  10
  11 int gethostbyname2_r(const char *name, int af,
  12         struct hostent *h, char *buf, size_t buflen,
  13         struct hostent **res, int *err)
  14 {
  15         struct address addrs[MAXADDRS];
  16         char canon[256];
  17         int i, cnt;
  18         size_t align, need;
  19
  20         *res = 0;
  21         cnt = __lookup_name(addrs, canon, name, af, AI_CANONNAME);
  22         if (cnt<0) switch (cnt) {
  23         case EAI_NONAME:
  24                 *err = HOST_NOT_FOUND;
  25                 return ENOENT;
  26         case EAI_AGAIN:
  27                 *err = TRY_AGAIN;
  28                 return EAGAIN;
  29         default:
  30         case EAI_FAIL:
  31                 *err = NO_RECOVERY;
  32                 return EBADMSG;
  33         case EAI_MEMORY:
  34         case EAI_SYSTEM:
  35                 *err = NO_RECOVERY;
  36                 return errno;
  37         }
  38
  39         h->h_addrtype = af;
  40         h->h_length = af==AF_INET6 ? 16 : 4;
  41
  42         /* Align buffer */
  43         align = -(uintptr_t)buf & sizeof(char *)-1;
  44
  45         need = 4*sizeof(char *);
  46         need += (cnt + 1) * (sizeof(char *) + h->h_length);
  47         need += strlen(name)+1;
  48         need += strlen(canon)+1;
  49         need += align;
  50
  51         if (need > buflen) return ERANGE;
  52
  53         buf += align;
  54         h->h_aliases = (void *)buf;
  55         buf += 3*sizeof(char *);
  56         h->h_addr_list = (void *)buf;
  57         buf += (cnt+1)*sizeof(char *);
  58
  59         for (i=0; i<cnt; i++) {
  60                 h->h_addr_list[i] = (void *)buf;
  61                 buf += h->h_length;
  62                 memcpy(h->h_addr_list[i], addrs[i].addr, h->h_length);
  63         }
  64         h->h_addr_list[i] = 0;
  65
  66         h->h_name = h->h_aliases[0] = buf;
  67         strcpy(h->h_name, canon);
  68         buf += strlen(h->h_name)+1;
  69
  70         if (strcmp(h->h_name, name)) {
  71                 h->h_aliases[1] = buf;
  72                 strcpy(h->h_aliases[1], name);
  73                 buf += strlen(h->h_aliases[1])+1;
  74         } else h->h_aliases[1] = 0;
  75
  76         h->h_aliases[2] = 0;
  77
  78         *res = h;
  79         return 0;
  80 }